Deputies responded to reports of an armed robbery at Subway in Pontiac at Walton Blvd.
Upon arrival, deputies interviewed the first victim, who said she was in the back cleaning dishes, when she heard the front door open.
The 48-year-old victim said that she came to the front and noticed the suspect, who was described as a black man wearing all-black clothing and a mask.
The suspect reportedly pointed a handgun at her and demanded all the cash from the register.
She said she opened the cash register and began to hand cash to the suspect.
Deputies interviewed a second victim, who stated he was in the men's restroom, and when he returned, he saw the suspect standing at the cash register.
The suspect pointed the gun at him, and he was directed by the suspect to go to the back room. The second victim activated the panic alarm, as the suspect left the establishment on foot with approximately $100.
Deputies were unable to review the store surveillance video or recover any physical evidence. Neither victim was injured during the incident.
Police say this may be the same suspect who recently robbed a Little Caesars in Auburn Hills.